What can be done to quiet a Kohler generator?

Wow, it is very quiet in the cockpit compared to the old single stage, a great improvement. It will be far less noticeable to us in the cockpit when visiting with friends. It did not change the cabin as much as that noise is directly from the unit not exaust noise, but still it was an impovement there as well. I seemed to have the same exaust water flow as with the single stage. MM
 
Guys, does the water coming out of your genny exhaust appear 'milky' thousands of tiny bubles?
Is it an early indication that the impeller needs replacing?
 
I have changed my oem generator stuff to the onan muffler and resonator (2 different units) and it made a huge difference. Different brands but a similar concept it seems...

Can you provide bit more details on your installation. Is there a big difference between the unit Tom and Mike installed and the one you got from Onan? I'm trying to understand if the one you got is more applicable to my boat as our units could be very similar. I'd love to modify my exshaust as it too noisy.

I just searched all through the house for a small flat mirror so I could get the info off of the decal, but in a house full of girls, not one!?...

Tom,

One of the tricks I use is the telescopical tripod for my camera. It's able to adjust to different angles at the top end so when I extent the tripod legs I'm able to reach behind stuff that are unreachable otherwise.
 
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Thanks for the update Mike. Do you have what the correct part number ended up being? Any pics?

It looks just like the pic in post #43 (with outlet variation) and my original was in post #48. The new on has the low side inlet and a high side outlet as opposed to the low in and top out they orriginally sent and Tom has pictured. As for part number, that will vary from vessel to vessel as to where you need the outlet. The link below will show you the dimensions they offer and will give you an idea what will fit where. Mine has 2 inch exaust lines in and out. MM

http://www.centekindustries.com/vernalift_dual_side.html
 
I just changed from a Centek single stage to a dual stage muffler (part number 1601345 - it is available but it is not shown on there website). It does make a difference but not dramatic. The ambient noise in the cockpit was about 30-35 db during these measurements. With the single stage, the sound was 65 db in the cockpit, 88 db in the bilge, and 76 db close to the exhaust. With the dual stage, the sound was 61 db in the cockpit, 88 db in the bilge, and 72 db close to the exhaust.

http://www.gcaudio.com/resources/howtos/loudness.html

You can see from the above chart a 5 db change can clearly be noticed. I was hoping for the 10 db drop. Oh well, off to my next sound proofing project...

I think I am going to mount the generator on isolators to decouple it from the boat structure.

I was given 2 other options from Centek that supposedly would be quieter but I did not have the physical space to utilize them. One was using a Combo-Sep and the other was keeping the old single stage muffler and adding a Gen-Sep. I could not mount either one of these due to the amount of vertical space required. You have to have so many inches above the water line and so many inches below the generator exhaust elbow that they just physically would not work.
 
I just changed from a Centek single stage to a dual stage muffler (part number 1601345 - it is available but it is not shown on there website). It does make a difference but not dramatic. The ambient noise in the cockpit was about 30-35 db during these measurements. With the single stage, the sound was 65 db in the cockpit, 88 db in the bilge, and 76 db close to the exhaust. With the dual stage, the sound was 61 db in the cockpit, 88 db in the bilge, and 72 db close to the exhaust.

http://www.gcaudio.com/resources/howtos/loudness.html

You can see from the above chart a 5 db change can clearly be noticed. I was hoping for the 10 db drop. Oh well, off to my next sound proofing project...

I think I am going to mount the generator on isolators to decouple it from the boat structure.

I was given 2 other options from Centek that supposedly would be quieter but I did not have the physical space to utilize them. One was using a Combo-Sep and the other was keeping the old single stage muffler and adding a Gen-Sep. I could not mount either one of these due to the amount of vertical space required. You have to have so many inches above the water line and so many inches below the generator exhaust elbow that they just physically would not work.

Did you check cabin levels? Interesting info, MM
 
Good info there. I think with the dual stage muffler, mine is plenty quiet. I actually think the bilge blowers are the loudest of it all.
 
I did not check the cabin levels. I can get a level with the new muffler though. In the cabin the problem is more the vibration transmitted through the boat structure than the actual sound.

John
 
Yeah, we have pretty much the same boat. I have sent an email to soundown.com asking their advice on further sound dampening and vibration isolation. I have not heard back yet.

John
 
Wow, it is very quiet in the cockpit compared to the old single stage, a great improvement. It will be far less noticeable to us in the cockpit when visiting with friends. It did not change the cabin as much as that noise is directly from the unit not exaust noise, but still it was an impovement there as well. I seemed to have the same exaust water flow as with the single stage. MM

Update: We had a weekend we were on the hook and used the generator quite a bit. The Admirals verdict was the muffler change was a big improvement and worth the cost. We were rafted up with another 5K Kohler and they also noticed how much quieter it is. We continue to be pleased with this upgrade. MM
 
I just searched all through the house for a small flat mirror so I could get the info off of the decal, but in a house full of girls, not one!? Go figure. If I find one, I'll be sure to post the results.

Tom

Well...better late than never I guess. I just replaced the batteries this past weekend and while I had the clear space, I cleaned up the bilge area around there and remembered this thread. I was able to sneak my cell phone in there and capture a photo of the label for the generator muffler.

GeneratorMuffler3.jpg


GeneratorMuffler2.jpg


The end of that label says "Sea Ray 1215128", and there is a date "07/22/10".

Tom
 
Tom, I do not see that unit on Centek's website. Probably SR specific.

MM

I was just re-reading through some of this thread and came across post #66 from LoneRanger where he mentions he has the exact same model number...and you are right, he said it does not appear on their website.

Tom
 
FYI, my Kohler 5ec gen. (2008 vintage) with sound shield is very quiet. Can barely be heard with engines off and not al all with engines on at idle.
 
FYI, my Kohler 5ec gen. (2008 vintage) with sound shield is very quiet. Can barely be heard with engines off and not al all with engines on at idle.

John, Most of us discussing this issue have our generator in a VERY tight space with no room for a sound shield. The dual stage muffler is very good to reduce our sound levels with the spaces we have.

MM
 

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